Download Unit 3, Lesson 2 Template

Unit 3, Lesson 2 of 3
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Periodic Table Trends
OBJECTIVE: After this lesson, I will understand the basic trends found in the Periodic Table, and I will
understand how the trends relate to specific elements.
Recall that elements from the same Group will have similar qualities, such as their basic classification. Today we
will see that there are other trends that run throughout the Table and once again, elements from the same Group
have similar: Atomic Radii sizes, Ionization Energies, and Electron Affinities. These trends are largely
responsible for the element interactions that lead to the formation of bonds and compounds.
Atomic Radius:
The trends and resulting properties of specific elements can often be related back to the nucleus. Recall that there
is an attraction between the electrons in the orbitals and the protons in the nucleus. The force or power of
attraction between an electron and the nucleus is dependent on the magnitude of the net nuclear charge acting on
the electron and the average distance between the nucleus and the electron. The force of attraction increases as the
nuclear charge increases and decreases as the electron moves farther from the nucleus.
Effective Nuclear Charge:
Unit 3, Lesson 2 of 3
Ionization Energy:
Blips/Exceptions:
Electron Affinity:
Blips/Exceptions:
Electron Affinity vs. Electronegativity
While often used interchangeably, electron affinity and electronegativity are not the same. Electron affinity refers
to an atom’s attraction for an electron, while electronegativity refers to an atom’s attraction for an electron in the
context of a bond. We will talk extensively about electronegativity in Unit 4.
Unit 3, Lesson 2 of 3
Metallic Character:
Summary of Periodic Trends
Unit 3, Lesson 2 of 3
Practice Problems
1. Arrange the elements S, Ge, P, and Si in order of increasing atomic size.
2. Arrange the elements Be, Ca, N, and P in order of increasing ionization energy.
3. Which elements fit the following descriptions:
a. the smallest alkaline earth metal
b. has a valence shell configuration 4f14 5d10 6s1
c. the halogen with the lowest ionization energy
d. has 13 more electrons than argon
e. the smallest non metal
f. the Group 4A element with the largest ionization energy
4. Based on the concept of periodic trends, answer the following questions for these atoms: Li, Be, Mg, Na
a. Which element has the highest first ionization energy?
b. Which element has the lowest electron affinity?
c. Which element has the least metallic character?
d. Which element is the largest atom?
5. Based on the concept of periodic trends, answer the following questions for these atoms: P, S, Cl, F
a. Which element has the highest first ionization energy?
b. Which element has the highest electron affinity?
c. Which element has the least metallic character?
d. Which element has the smallest atom?
6. Based on the concept of periodic trends, answer the following questions for these atoms: Au, Zn, S, Si
a. Which element has the highest first ionization energy?
b. Which element has the highest electron affinity?
c. Which element has the most metallic character?
d. Which element has the largest atom?